Electrical relay



P. N. MARTIN vELECTRICM.; RELAY March 28, 1944.

Filed Nov. 5, 1942 :1T/5 ff fg. z.

I :ff/2a ff@ Af INVENTOR 10aa! A( @Pb BY @v /ifwlbvf HIJ ATTORNEY Patented Mar. 28, 1944 ELECTRICAL RELAY Paul N. Martin, Penn Township,

Allegheny County, Pa., assigner to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application November 5, 1942, Serial No. 464,671

5 Claims.

My invention relates to electrical relays, and particularly to relays of the direct current polarized type.

One object of my invention is to provide a polarized relay with a polar armature that always moves to one position due to the force of gravity when the relay is deenergized.

Another object of my invention is to provide a polarized relay which is not liable to false operation of the polar armature if one of the permanent magnets should become reversed in polarity due for example to a heavy surge current such as sometimes results from lightning discharges.

According to one form of my invention, the polar armature of the relay is pivotally supported at one end adjacent to one pole of the relay electromagnet and cooperates at its free end with the unlike poles ci two vertically spaced permanent magnets which are magnetically connected with the other pole of the relay electromagnet.

According to another form of my invention, the polar armature is pivotally supported intermediate i'rs ends, and has one end disposed between vertically spaced polar extensions provided on one pole of the relay electromagnet and the other end disposed between the unlike poles of two vertically spacedpermanent magnets connected with the other pole of the relay electromagnet.

Other cbjects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe two forms of relays embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Fig, l is a diagrammatic view showing one form of relay embodying my invention. Fig. 2 is a View similar to Fig, 1 showing a modied form of the relay illustrated in Fig. 1.

Similar reference characters refer to similar parts in both views.

Referring rst to Fig. 1, the relay comprises an electromagnet A of the usual type having two parallel cores Ia and Ib connected together at their upper ends by a backstrap 2 and provided at their lower ends with pole pieces 3a and 3b, respectively. The core Ia carries the usual operating winding da, and the core Ib carries a similar winding 4b. These windings are connected in series to lprovide cumulative magneto-motive forces in the cores la and Ib, and are arranged to be supplied with current of normal or reverse relative polarity from a battery 23 according as the contacts 5 and E of a pole lll changer P are moved to their upper or lower positions.

A neutral tractive armature 1 is pivotally supported adjacent one end at 8 for swinging movement toward or away from the pole pieces 3a and 3b according as the electromagnet A is en ergized by current of either polarity or is deenergized, and attached to this armature by means of an insulating support 9 is a contact nger II1 which cooperates in the usual manner with a fixed front contact Ia or a xed back contact IIlb to close a front contact IU-Ia or a back contact III-IDD.

The relay also comprises a polar armature Il which is pivotally supported at one end at I 2 adjacent to a polar extension I3 formed on the core lb at the same end of the core as the pole piece 3b. The other end of the polar armature Ii is disposed between and cooperates with two vertically spaced permanent magnets I4 and I5 which are magnetically connected with the core Ia at the same end of the core as the pole piece 3a. The permanent magnets are so disposed that their ends adjacent to the armature II are of opposite polarity, and the armature is biased by gravity to the position in which it is swung toward the lower magnet I4. The polar armature, however, may at times be moved against the action of gravity to the position in Which it is swung toward the magnet I5, as will be explained more fully hereinafter. Attached to the armature II by means of an insulating support I6 is a Contact nger I 'I which cooperates with a nxed contact member I'Ia or a fixed contact member I lb to close a polar contact I'I-I 'la or a polar contact I'I-IIb according as the polar armature is swung toward the permanent magnet I4 or the permanent magnet I5.

With the relay constructed in this manner, the neutral armature will be attracted toward the pole pieces 3a and 3b to open its back contact Ill-I 0b and close its front contact IU-I Ila when the operating windings 4a and 4b are supplied with operating current of either polarity, but the polar armature I I will. move to its upper portion to open the polar contact I'I--I`Ia. and close the polar contact l*ilb when and only when the windings 'la and 4b are energized by current of such polarity that the magnetic flux induced in the cores ia and Ib tends to traverse the polar armature in the same direction as that due to the upper permanent magnet I5. That is to say, assuming that the ends of the permanent magnets I5 and I4 nearest the polar armature II are north and south poles, respectively, as indicated traverse the polar amature due to the upper permanent magnet, and under these conditions the polar armature will move to its upper position, in which contact I'I--IIb becomes closedfand' the contact I'I-I'Ia becomes opened. When, however, the windings 4a and 4b are energized by current of reverse polarity,` so that the lower end of the core Ib becomes a north pole and the lower end of core Ia a south pole, the ux due to the electromagnet will then aid the flux which tends to traverse the polar armature from the lower permanent magnet and oppose that which tends to traverse the polar armature from the upper permanent magnet, and under these latter conditions the downward pull on the polar armature will merely be increased and the polar armature will remain in the position shown.

The weight of the. polar armature, the air gap between it and the upper magnet when it occupies its upper position, and the permanent magnet strength are so chosen that if the polar armature occupies its upper position when the windings @a and 4b become deenergized, the polar armature will immediately move to itslower position in which it is swung toward the lower magnet I4. If the polar armature already occupies its lower position when the windings 4a and 4b becomel deenergized, it will of course remain in this position. k

It should be pointed out that the above described operation can only be obtained when the permanent magnets are of opposite polarity, and as a result if one of the permanent magnets should become reversed in polarity for some reason, such for example as might occur due to a heavy surge current in the windings 4a, and 4b caused leva lightning discharge, the gravity bias on thearmature II together with the fact that when this armature occupies the position shown the airrgap between it and the lower magnet is smaller than the air gap kbetween it and the upper magnet will cause it to release if it is picked up when'the reversal occurs, and if it is already released whenthe reversal occurs will cause it to remain in its related position. It should also be pointed out that the arrangement of the permanent magnets is such that any surge current which might be set up would tend to makev both permanent magnets of the saine polarity.

A relay of the type described is particularly suitable for, although in no way limited to, use for controlling the red, yellow and green lights of the usual railway signal to cause the signal to display its stop, caution and proceed aspects. When used for this purpose, the red lamp R would be supplied with current from the terminals B and C of a suitablel source over the back contact Ill- I b so that this lamp would be lighted whenever the relay is deenergized, the yellow lamp Y would be supplied with energizing current from the terminals B and C over the front contact I--Ia and the polar contact II-IIa in series so that this lampr would be lighted whenever the relay is energized with current of reverse relative polarity, and the green lamp G would be supplied with energizing current over the front contact I0--I0a and the polar contact I'I-I'Ib so that this lamp would be energized whenever the relay is energized by current of normal polarity. With a signal controlled by the relay in this manner if one of the magnets should become reversed, the green lamp will not become lighted, and it follows that the possibility of false clear failures is less likely than with the conventional type of polar relay generally employed.

Referring now to Fig. 2, the relay here shown differs from that shown in Fig. 1 in that the polar armature, which is here designated IIa, is pivotally supported intermediate its ends at I2a, and has one end disposed between the polar extension- I3 and another polar extension Ilia provided on the core Ib below the extension I3. The other end of the polar armature IIa is disposed between the unlike poles of the permanent magnets I5 and It, respectively. The polar armature IIa controls polar contacts I 'I-IIa and I'I-I'Ib in a manner similar to the polar armature II.'Y

The operation of the relay when constructed as shown in Fig. 2 diiers from that shown in Fig. 1 in that since the polar armature is pivotally supported intermediate its ends it has no gravity bias, and consequently when the relay becomes deenergized the armature will be held in its last energized position by the polarizing flux from the contiguous permanent magnet. If desired, however, the polar armature may be biased to the position shown in the drawing by a weight or spring in whichevent the operation of the relay will be similar to the operation of the relay shown in Fig. l.

Although I have herein shown and described only two forms of relays embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention. Y

Having thus described my invention, what I claim is:

1. An electrical relay comprising a pair o1 Cores connected at one end by a backstrap and i provided at the other end with pole pieces, energizing windings disposed on said cores, a neutral armature movable toward and away from said pole pieces, a pair of permanent magnets connected at one end with one core at the same end as the associated pole piece and having their free ends oppositely poled and disposed in parallel spaced relation, and a polar armature magnetically connected with the other core oi said electromagnet at the same end as the associated pole piece and mounted-to move toward one or the other of the free ends of said permanent magnets.

2. An electrical relay comprising a pair of cores connected at one end by a backstrap and provided with energizing windings, a polar extension provided on the one core Vat the end opposite to said backstrap, a pair of permanent magnetsconnected at one end to the other core at the end opposite to said backstrap and having their free ends vertically spaced and oppositely poled, and a polar armature pivotally supiported at one end adjacent to said polar extension and movable at its other end between the free ends of said permanent magnets.

3. An electrical relay comprising a pair of cores connected at one end by a backstrap and provided with energizing Ywindings, a pair of vertically spaced 'polar extensions provided on one core at the endopposite to said backstrap, a pair of permanent magnets connected at one end to the other core at the end opposite to said backstrap and having the free ends oppositely poled and disposed opposite said polar extensions respectively, and a polar armature pivotally supported intermediate its ends and cooperating at its opposite ends with said polar extension and with the free ends of said permanent magnets, respectively.

4. An electrical relay comprising a pair of cores connected at one end by a backstrap and provided with energizing windings, a polar extension provided on the one core at the end opposite to said backstrap, a pair of permanent magnets connected at one end to the other core at the end opposite to said backstrap and having their free ends vertically spaced and oppositely poled, a polar armature pivotally supported at one end adjacent to said polar extension and movable at its other end between the free ends of said permanent magnets, and a neu- 20 tral armature cooperating with pole pieces provided on said cores at the ends opposite to said backstrap.

5. An electrical relay comprising a pair of cores connected at one end by a backstrap and provided with energizing windings, a pair of vertically spaced polar extensions provided on one core at the end opposite to said backstrap, a pair of permanent magnets connected at one end to the other core at the end opposite to said backstrap and having the free ends oppositely poled and disposed opposite said polar extensions respectively, a polar armature pivotally supported intermediate its ends and cooperating at its opposite ends with said polar extension and with the free ends of said permanent magnets, respectively, and a neutral armature cooperating With pole pieces provided on said cores at the ends opposite to said backstrap.

PAUL N. MARTIN. 

